Thermostatic switch



. w 1,519,747 H. N. WADE- THERMOSTATIC SWITCH Filed Nov. 24. 1919INVENTOR.

Patented Dec. 16, 1924.

UNITED STATES PATENT. OFFICE.

HENRY N. WADE, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO THE CUTLER-HAMMER00., OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

'rnnnuos'ra'rlc swrtron.

Appllcationfflled November 2 4, 1918. Serial No. 840,205.

Toull w/mm it mrq concern:

Be it knowirlha't I, llarnn' N. VVAnu, a citizen of. the United States,residing at lililwaukec, in the county of Milwaukee and State of-'iseonsin, have invented new and useful Improvements in ThermostaticSwitches, of which the following is a full, clear, concise. and exactdescription, reference being had to the accompanying drawing, forming apart of this specification. This invention relates to thermostaticswitches adapted for various uses as in heating and refrigeratingsystems.

The present forms of thermostatic switches employ 'solid contacts anddue to the slow motion of the thermal operating means commonly employed,such contacts tend to draw destructive arcs unless'additional-means areprovided to insure quick disengagement thereofl Also, owing to the slowclosure of such switches any vibrations thereof during closure tend tocause their contacts to vibrate which often results in further arcingand sometimes welding of the contacts.

The present invention hasamon its objeets to provide a simple and-reliale ther niostatic switch which will overcome the aforesaid and otherdisadvantages of the present thermostatic switches.

Another object is to provide a therinostatic switch which will minimizethe work re uired'of the thermal means.

ther ob'ects and advantages of the invention will hereinafter appear. v

The accompanying drawing illustrates one embodimentbf the inventionwhich will now be described, it being understood that the same issusceptible of various modifications falling-within the scope of theappended claims.

Referringto the drawing, the structure shown therein com rises a mercuryswitch 1 fixed to an insu ating sector 2 mounted upon a knife edge pivotstud 3 projecting from a support Lands. thermal element 5 foroscillating the sector. 2.

The switch lcomprises an insulating ves-. eel, preferably a glass tube,contaimn a quantit of mercury or other preferred uid 6 and ll wires 7and 8 to be bridged by the mercury. The tube is provided with wells 9and 10 for the mercury, the quantity of which is able stud 22' providinaving sealed in its ends terminal sullicient to bridge said wells andthe extremities of the terminal wires 7 and 8 are arranged to extendinto said wells for constant immersion. Thus it will be apparent eventhough the switch be tilted' very slow 1). Similarly, return of theswitch to the position illustrated will cause-1the main body of themercury to recombine with-the mercury in the well or wells for a quickand decisive closure of the circuit between the terminal wires. I 5 iAlso, the tube is preferablysd formed and mounted as to render themercury supporting surface thereof, exce t for t e wells, concentric tothe pivot o the sector 2 whereby the center of gravityof the bulk of themercury will remain substantially fixed vertically when the switch istilted by pivotal movement of the sector which is preferably providedwith a counter-balance 11. Suchprovisions render the switch operable bya very slight force, thus minimizing' the work required of the thermalmeans. The'switch is provided with ferrules 12 and 13 fitted to the endsthereof and electrically connected with the terminal wires 7 and 8respectively. The sector is provided with conducting cli s 14 and 15 .to13 respectively support 4; The clips 14 and 15 have conducting loads 17and 18 respectively which are coiled about the hub of sector 2 andconnected to binding posts -19' and 20 respectively provided on thesupport 4;.

The thermal element, which in practice may assume various forms is shownas-comprising a bimetallic strip connected at one end to a post 21 onthe supportf4 and havingits opposite end connected to a stud 22 mountedon the sector and adjustable radially thereof. The thermal stripisutilized to 'rotate the'e'ector clockwise, thea'd'ustfor variation 0 therange of movement o said disk for a given temperature variation. Pithsuch an arrangement the mercury ivides adJacent t0 the well 9 forinterruption of circuit a1 though it is to be unde1stood that the stop16.might be placed 'onthe' opposite side of; the sector and the thermalstrip employedto-Erotate the sector counterclock ise to divide themercury adjacent to the well 1.0. Thus" the switch -may be readilydesigned to open circuit either upon an' increase or decreaseoftemperature as desired and as will-be apparent the switch might benormally. held in a positionto interruptcircuit instead of in circuitclosing position as shown. I

If adjustability of the thermal element is desired such adjustment-maybe accomprising amovable element containing a conductive fluid, saidelement having means for lifting a relatively small amount of such fluidfrom the remainder thereof for circuit breaking, a knife-edge pivotedcounterbalanced oscillatable support for said movable element providing.for movement of said element. to control circuit while maintaining thecollective center of gravity of said element and" said supportsubstantially undisplaeed vertically, of thermo-rcsponsive means for soactuating said supp ort. V a

3: The combination with a switch com- 16 plished -in various 'ways, asby adjustment prising a movable element containing a conductive fluid,said element having means 1 cure by Letters ,Patentis:

of the post'21 rotarily, said post being mounted for such adjustment andbein )rovided with means 23 to indicate the a' 1ust1nent thereof.

What I claim as new and desire to se- L-The combination with a switchcomrisin a counter-balanced movable element containing a conductivefluid, said element having means for lifting a relatively small amountof such fluid from the remainder thereof for circuit breakingofthermo-re-' sponsive means for so operating said switch 'whilemaintaining the center of gravity of said inovable element'and thecontained conductive ,fluid tically.

2. The combination with a switch comsubstantially undisplaced verforseparating a'relatively-small amount of such fluid froml the remainderthereof for circuit breaking, a knife-edge pivoted counterbalancedsupport for said element providing for movement thereof to controlcirunit while maintaining the collective center of gravity of saidelement and said support substantially undisplaoed vertically, ofad'ustable thcrmo-responsivemeans connecte with said support foractuating the same, and means for varying the range of movement of saidsupport under given thermal conditions.

In .witness whereof, I have hereunto subscribed my name.

HENRY N. WADE.

